How many moles of ammonia are produced by $5$ moles of hydrogen (in $.3$)?

$120 \ g$ of urea are present in $5 \ L$ of solution. The active mass of urea is:

Find the weight in grams of carbon monoxide $(CO)$ that contains the same number of oxygen atoms as are present in $22 \ g$ of carbon dioxide $(CO_2)$.

At $S.T.P.$,$1 \ g$ $CaCO_3$ on decomposition gives $CO_2$ ............. $litres$.

What is produced when $1 \ mol$ of calcium phosphide reacts with excess water?
$(Hint: Ca_3P_2 + H_2O (excess) \rightarrow Ca(OH)_2 + 2PH_3)$

The molarity of $1 \ L$ orthophosphoric acid $(H_3PO_4)$ having $70 \%$ purity by weight (specific gravity $1.54 \ g \ cm^{-3}$) is $ . . . . . . $ $M$.
(Molar mass of $H_3PO_4 = 98 \ g \ mol^{-1}$)